Rehomed `Playwright.ChannelOwner` into `Playwright.SDK`.

Rehomed `Playwright.Channel` into `Playwright.SDK`.

Rehomed `Playwright.CLI` into `Playwright.SDK`.

Rehomed `Playwright.Config` into `Playwright.SDK`.

Rehomed `Playwright.Transport` into `Playwright.SDK`.

Rehomed `Playwright.Channel.*` into `Playwright.SDK`.

Rehomed `Playwright.Extra.*` into `Playwright.SDK`.

Rehomed `Playwright.Helpers.*` into `Playwright.SDK`.

Rehomed `test/unit` as `test/sdk`.

- Switch to pinning to specific versions of playwright and electron node
  packages. We should be matching.
- Simplify the asset packaging approach. Starting at v1.38 of Playwright
  (proper), using `esbuild` got much harder, and the benefits seem less
  evident. So, we're now doing a basic `cp` of what's needed.
- Bump playwright_assets to latest, in preparation for what's to come.
- Switch to `driver.js`, replacing `playwright_cli.js`; it feels nicer and
  matches the Elixir module naming.

This change is primarily to prove out the rest of what was needed in order to
make this version bump to playwright.js; a follow-on will bump up to the
latest.

It turns out the module fails to load if saved as a script.

These changes bring playwright-elixir's integration with playwright server up
to date with playwright-core v1.38.0, which appears to have had a number of
breaking changes (for our SDK). Of note:

- Update WebSocket transport to send browser type as a header, per
  recent Playwright Server API changes.
- Implement `Playwright.connect`, for WebSocket transport sessions.
- Update `ws://...` endpoint to match Playwright Server changes
- Clarify options for `Playwright.connect` vs. `Playwright.launch`
- Add debug handling of a potential serialization bug. Note that this
  may have occurred as a side effect of other Playwright Server
  integration issues that have been fixed.

Yet again, this upgrade changes how the Playwright CLI/program is execute. So,
this change also includes a more static defintion of `driver.js`; one that will
probably need to be reworked periodically.

Some of which stem from internal changes, some from changes to playwright-core.

According to Playwright.dev, accessibility testing should be executed with
separate, spacialized libraries. The Playwright implementation is deprecated.

This change also removes a failing test, in keeping with the matching removal
from Playwright proper. It appears that the browser behavior was considered to
be too inconsistent.

Also, clean up locked deps.